This invention relates to a data processing system with a plurality of processors and, more particularly, to a data processing system of this type capable of initializing the individual processors.
As complicated computer systems having functional versatility have come into practical use, the need arises for higher system reliability. Improved reliability results from scheduled maintenance or routine inspection for the computer system as well as improvements in performance of parts and components constituting the system. A conventional computer system is automatically diagnosed at the initializing stage to detect faults of the system. In response to a fault detection the system operation is stopped. For details of the system diagnosis at the initializing stage, reference is made to an article by A. M. Johnson titled "The Microdiagnostics for the IBM System 360 Model 30,"IEEE TRANSACTIONS ON COMPUTERS, Vol. C-20 No. 7, pages 798-803, July issue, 1971
A more effective system for the above-mentioned maintenance has recently been developed for practical use. In this system, a diagnostic program operates hardware or firmware, so that the system is forcibly operated in the worst operational condition. It follows consequently that defective parts are detected through the diagnosis and separated from the system, preventing erroneous operations from occurring while the system is in operation.
However, the above-proposed diagnosis techniques merely teach the detection of defective parts to separate them from the system with a single processor.
On the other hand, a multiprocessor system, which has a plurality of processors to improve the performance and reliability of the system, has been put into practical use. For details of the system construction at the initializing stage in such a conventional multiprocessor system, reference is made to "CONFIGURATION CONTROL" of IBM System/370 Model 168 Functional Characteristics, pages 48-49, published in 1976 by International Business Machine Corporation. According to this technique, an interface connection among processors is specified by a system-mode switch provided on the control panel. Then, a system-reset switch and a load switch, which are similarly provided on said panel, are operated in succession for initializing the system. As a result, the multiprocessor system is constructed as specified by the system mode switch, so that software is immediately loaded and executed by the individual processors. When the system is operated through the initializing operation as above mentioned, however, there is still a possibility of the so-called system down while in running.
An object of the invention is, therefore, to provide a data processing system with a plurality of processors free from the above-mentioned system down to maintain higher reliability of the system operation.
Another object of the invention is to provide a data processing system which automatically executes a system diagnosis at the initializing stage.
Yet another object of the invention is to provide an improved data processing system capable of automatically separating defective processors from the system in response to the result of the diagnosis.